Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Impact of disorder on dynamics and ordering in the honeycomb-lattice iridate Na2IrO3

Journal Article · · Physical Review B
 [1];  [2];  [3];  [3];  [1];  [3];  [4];  [2]
  1. Technical Univ. of Dresden, Dresden (Germany). Inst. of Solid State and Materials Physics
  2. Univ. of California, Davis, CA (United States). Dept. of Physics
  3. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Univ. of Colorado, Boulder, CO (United States); National Inst. of Standards and Technology (NIST), Boulder, CO (United States). JILA
+ Show Author Affiliations
Kitaev's honeycomb spin-liquid model and its proposed realization in materials such as α-RuCl3, Li 2IrO3, and Na2IrO3 continue to present open questions about how the dynamics of a spin liquid are modified in the presence of non-Kitaev interactions as well as the presence of inhomogeneities. Here we use 23Na nuclear magnetic resonance to probe both static and dynamical magnetic properties in single-crystal Na2IrO3 . We find that the NMR shift follows the bulk susceptibility above 30 K but deviates from it below; moreover below TN the spectra show a broad distribution of internal magnetic fields. Both of these results provide evidence for inequivalent magnetic sites at low temperature, suggesting inhomogeneities are important for the magnetism. The spin-lattice relaxation rate is isotropic and diverges at TN, suggesting that the Kitaev cubic axes may control the critical quantum spin fluctuations. Finally, in the ordered state, we observe gapless excitations, which may arise from site substitution, emergent defects from milder disorder, or possibly be associated with nearby quantum paramagnetic states distinct from the Kitaev spin liquid.
Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
Deutsche Forschungsgemeinschaft (DFG); National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1616111
Journal Information:
Physical Review B, Journal Name: Physical Review B Journal Issue: 8 Vol. 101; ISSN 2469-9950; ISSN PRBMDO
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English

References (34)

A spin–orbital-entangled quantum liquid on a honeycomb lattice journal February 2018
Direct evidence for dominant bond-directional interactions in a honeycomb lattice iridate Na2IrO3 journal May 2015
Kitaev matter journal May 2015
Scaling and data collapse from local moments in frustrated disordered quantum spin systems journal October 2018
Observation of two types of fractional excitation in the Kitaev honeycomb magnet journal May 2018
Concept and realization of Kitaev quantum spin liquids journal March 2019
Nuclear magnetic resonance in the heavy fermion superconductors journal January 2009
Nuclear magnetic resonance Knight shifts in the presence of strong spin–orbit and crystal-field potentials journal July 2016
Nuclear Spin-Lattice Relaxation in Magnetic Insulators journal February 1968
Antiferromagnetic Mott insulating state in single crystals of the honeycomb lattice material Na 2 IrO 3 journal August 2010
Local magnetic inhomogeneities in Ba ( Fe 1 − x Ni x ) 2 As 2 as seen via A 75 s NMR journal October 2010
Long-range magnetic ordering in Na 2 IrO 3 journal June 2011
Direct evidence of a zigzag spin-chain structure in the honeycomb lattice: A neutron and x-ray diffraction investigation of single-crystal Na 2 IrO 3 journal May 2012
Magnetic order and spin dynamics in La 2 O 2 Fe 2 OSe 2 probed by Fe 57 Mössbauer, La 139 NMR, and muon-spin relaxation spectroscopy journal November 2014
Dynamics of fractionalization in quantum spin liquids journal September 2015
Local magnetism and spin dynamics of the frustrated honeycomb rhodate Li 2 RhO 3 journal September 2017
Chemical and hydrostatic-pressure effects on the Kitaev honeycomb material Na 2 IrO 3 journal September 2018
Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models journal January 2009
Relevance of the Heisenberg-Kitaev Model for the Honeycomb Lattice Iridates A 2 IrO 3 journal March 2012
Spin Waves and Revised Crystal Structure of Honeycomb Iridate Na 2 IrO 3 journal March 2012
Na 2 IrO 3 as a Novel Relativistic Mott Insulator with a 340-meV Gap journal December 2012
Zigzag Magnetic Order in the Iridium Oxide Na 2 IrO 3 journal February 2013
Dynamics of a Two-Dimensional Quantum Spin Liquid: Signatures of Emergent Majorana Fermions and Fluxes journal May 2014
Low-Energy Spin Dynamics of the Honeycomb Spin Liquid Beyond the Kitaev Limit journal July 2016
Evidence for a Field-Induced Quantum Spin Liquid in α - RuCl 3 journal July 2017
Gapless Spin Excitations in the Field-Induced Quantum Spin Liquid Phase of α − RuCl 3 journal December 2017
Anisotropic temperature-field phase diagram of single crystalline β − Li 2 IrO 3 : Magnetization, specific heat, and Li 7 NMR study journal July 2019
Valence Bonds in Random Quantum Magnets: Theory and Application to YbMgGaO 4 journal July 2018
The Effect of Electron-Electron Interaction on the Nuclear Spin Relaxation in Metals journal April 1963
Physics of the Kitaev Model: Fractionalization, Dynamic Correlations, and Material Connections journal March 2018
Physics of the Kitaev model: fractionalization, dynamical correlations, and material connections text January 2018
Low-energy Spin Dynamics of the Honeycomb Spin Liquid Beyond the Kitaev Limit text January 2016
Scaling and data collapse from local moments in frustrated disordered quantum spin systems text January 2018
Observation of two types of fractional excitation in the Kitaev honeycomb magnet text January 2018

Similar Records

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY